Add custom success messages for buttons
Persist controls across AJAX page changes

When a new video is selected the current video section of the page is
replaced by the new (without a reload) which removes the controls.
Extension now hooks the 'onYouTubePlayerReady' event to re-insert the
controls whenever a new player is loaded.
Run extension on results page

Fix for inserting controls on '/watch' page when coming from '/results'.